1. Field of the Invention
The present invention relates to a surveying apparatus provided with a camera for capturing an image in a surveying field.
2. Description of the Related Art
A surveying apparatus provided with a camera, such as a total station, a theodolite, etc., includes a telescope block for sighting. In general, the telescope block is rotatably supported by a support block (the body of the surveying apparatus) about a horizontal axis and the support block is rotatably supported by a leveling board about a vertical axis. In this type of surveying apparatus, electronic circuits of a phase modulation measurement module or a pulse laser module, and the imaging device of a camera, are installed inside the telescope block while a control circuit to control the entire system of the apparatus, an image signal processor, and an image-display device, are installed inside the support block.
Because of this, distance measurement data, angle measurement data, and image data are transmitted from the telescope block to the support block through a rotational electrical contact ring that is disposed between the telescope block and the support block. However, the available space for the rotational electrical contact ring to be disposed is limited so that as the number of contact points increases, the available size of each terminal for the contact points is reduced. Thereby, when a number of contact points are required, it is difficult to secure stable electrical communication via a rotational electrical contact ring over a wide range of temperatures from a low temperature to a high temperature. Conversely, when the number of contact points is decreased, the image signals are required to be transmitted as analog signals, so the resolution and/or the quality of the image deteriorate. Japanese Patent Publication No. 3281064, as a countermeasure, discloses a surveying apparatus that guides incident light from the sighting telescope from the telescope block to the support block through a shaft between the blocks, and an optical image projected on an imaging device provided inside the support block is captured.